The influence of caffeine consumption on the development of 7,12-dimethylbenz(a)anthracene-induced mammary carcinomas in BD2F1 female mice and spontaneous mammary carcinomas in nulliparous C3H mice was examined. Caffeine (250 and 500 mg/liter of drinking water) was administered to BD2F1 mice commencing 1 week after a series of 6 weekly 7,12-dimethylbenz(a)anthracene intubations, until experiment termination. Caffeine was administered to C3H mice (via drinking water) commencing at 8 weeks of age to experiment termination. In BD2F1 mice receiving 250 and 500 mg of caffeine, mammary carcinoma multiplicity (number of mammary carcinomas/mouse) was increased by 20 and 40%, respectively. In C3H mice receiving 250 and 500 mg caffeine, mammary carcinoma multiplicity was increased by 13 and 117%, respectively. In both BD2F1 and C3H mice, the higher dose level of caffeine resulted in a significant (P < 0.05) increase in mammary carcinoma multiplicity. Caffeine consumption did not significantly effect the percentage of mice bearing mammary carcinomas or the mean latency period of mammary tumor appearance. In a second series of studies, the influence of caffeine consumption on mammary gland development in female BALB/c mice was assessed in vivo and in vitro (organ culture). In mice consuming caffeine (500 mg/liter of drinking water), mammary gland development was significantly (P < 0.05) increased compared to control mice; this difference in mammae development was more conspicuous in mice treated with mammotropic hormones. In the organ culture studies, mammary glands derived from caffeine (500 mg/liter of drinking water) consuming BALB/c mice were more responsive in vitro to a mammotropic hormonal developmental growth stimulus than were mammae derived from control mice (P < 0.05). These results provide evidence that caffeine consumption can enhance mammary tumorigenesis in C3H and carcinogen-treated BD2F1 female mice and, in addition, enhance developmental growth of the normal female mouse (BALB/c) mammary gland.
This research was supported by NIH Research Grant CA-37613.